I made a bunch of changes to the Plone add-on which drives the current LibreOffice extensions website during the last weeks. I especially made it easy to enter the file extensions for extension, image and documentation files and change them if needed. This is possible without the need of any programming skills. I had to create new validators for this purpose and replace the old ones with them.
The new release of the Plone add-on ‘tdf.templateuploadcenter’ is available via the ‘Cheeseshop’ (https://pypi.org) yet:
https://pypi.org/project/tdf.extensionuploadcenter/
It is version 0.36 and you could download it from there or much easier include it into your buildout script.